A wind turbine comprises a rotor, with rotor blades and a rotor hub. The rotor hub is rotatable connected to a nacelle. The nacelle is arranged on a tower in a way that the nacelle is able to perform a yaw movement.
The tower of the wind turbine is connected to a foundation. Wind turbines can be installed onshore and offshore. An offshore installation requires a specialized installation vessel, to transport the parts of the wind turbine to the installation site.
First, the foundation is installed at sea. Then the tower is connected to the foundation, and the nacelle, the hub and the rotor blades are installed. The parts need to be shipped to the installation site and need to be lifted by a crane on the installation vessel.
The operation of the installation vessel is expensive and the costs are calculated by the installation time needed. Thus, the number of parts to be installed is minimized and the parts of the wind turbine are preinstalled.
The higher the level of the preparation of the parts, the less installation time is needed on sea. The tasks, that need to be performed at sea during the installation, are mainly to connect the parts of the wind turbine and install the arrangements that lead from one part to the neighboring part of the wind turbine.
It is known to install an elevator in the tower of a wind turbine. The elevator is used for personnel and parts during installation, maintenance and service. It is also known to install an elevator that connects the tower and the foundation of the wind turbine.
The tower is lifted by crane from the vessel and is connected to the foundation. After the installation of the main parts of the wind turbine, the elevator is installed in the tower of the wind turbine and in the foundation. The elevator needs to be adjusted, tested, and approved for the transportation of personnel and parts.
The installation of the elevator needs installation time and thus increases the costs of installation of the wind turbine.
Embodiments of the invention provide an improved elevator and method of installation.